solitary ground bees - Ask Extension
As the attached picture shows, the (solitary?) ground bees do a job on my lawn. They cause bare spots and each year I have to fight many more weeds an...
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solitary ground bees #832420
Asked May 28, 2023, 3:28 PM EDT
As the attached picture shows, the (solitary?) ground bees do a job on my lawn. They cause bare spots and each year I have to fight many more weeds and unsightly areas because of them. They expand their territory each year and are starting to go to the back yard. Our soil is very sandy.
I know we need pollenating bees but is there anything i can do to deter them from my lawn. They only extend 2 to 3 feet into my next door neighbor's yard and NO ONE else on my block has them. I use an organic lawn service and I'm wondering if something in their spray or granular fertilizer is attracting them. Don't want to kill them just want them to move! Picture attached.
Anne Arundel County Maryland
Expert Response
The products your lawn company may be using are not attracting the bees, but the opposite might be happening -- that the products neighbors are using on their lawns or insecticides used in their gardens might be killing-off (or at least repelling) the bees if they attempt to nest there. You are correct that these are highly valued pollinators (the majority will be native species) and as such we typically discourage gardeners from trying to get rid of them. Once they have begun nesting, if you interrupt their provisioning period (the females gathering pollen for their eggs in the burrow over the course of a few weeks), the larvae within might be doomed to die as they won't have enough food. The females seal them into the burrow once the stockpile of food for each egg/larva is complete, so she will not be able to replenish the food stores later as she dies before they have hatched.
If you aren't able to tolerate their activity, the ideal time of year to try to interrupt nesting with as little mortality as possible is probably just when the adults have appeared and are flying around finding mates but before they have begun to dig lots of burrows as the mated females begin to lay eggs. Then, they might be able to find suitable soils elsewhere, though habitat loss for nesting grounds is one reason an established colony should ideally be protected, since they have few alternatives to move to.
The burrows are aerating the lawn (a bonus for root and soil health), and if something is stressing the turf to the point of thinning or weed invasion then it's probably unrelated to the activity of the bees. These are solitary bees in that they don't help each other with a single nest (as truly social honey bees do) but aggregations of solitary bees tend to occur because they're all using favorable nesting conditions. Therefore, each female is solitary because she digs and provisions her own nest, but they don't cooperate even though they can form these dense "neighborhoods" of dozens of bees. (One assumes the congregating behavior also helps them find mates when the new generation emerges each spring.)
A laboratory soil test may help with assessing soil conditions that could be stressing the turf, though if you've had one performed in the past couple of years, its results should still be sufficient. If parts of the lawn that are struggling have become a bit more shaded over the years, such as from maturing shrubs and trees, then that may be a contributing factor to increasing weeds and declining lawn. We would need more information about the lawn's maintenance and images of its appearance in the areas that are struggling to help narrow-down possible causes. Since they don't bother people with regards to stinging, though, we'd encourage you to live with the relatively brief period of bee activity if possible.
Miri
If you aren't able to tolerate their activity, the ideal time of year to try to interrupt nesting with as little mortality as possible is probably just when the adults have appeared and are flying around finding mates but before they have begun to dig lots of burrows as the mated females begin to lay eggs. Then, they might be able to find suitable soils elsewhere, though habitat loss for nesting grounds is one reason an established colony should ideally be protected, since they have few alternatives to move to.
The burrows are aerating the lawn (a bonus for root and soil health), and if something is stressing the turf to the point of thinning or weed invasion then it's probably unrelated to the activity of the bees. These are solitary bees in that they don't help each other with a single nest (as truly social honey bees do) but aggregations of solitary bees tend to occur because they're all using favorable nesting conditions. Therefore, each female is solitary because she digs and provisions her own nest, but they don't cooperate even though they can form these dense "neighborhoods" of dozens of bees. (One assumes the congregating behavior also helps them find mates when the new generation emerges each spring.)
A laboratory soil test may help with assessing soil conditions that could be stressing the turf, though if you've had one performed in the past couple of years, its results should still be sufficient. If parts of the lawn that are struggling have become a bit more shaded over the years, such as from maturing shrubs and trees, then that may be a contributing factor to increasing weeds and declining lawn. We would need more information about the lawn's maintenance and images of its appearance in the areas that are struggling to help narrow-down possible causes. Since they don't bother people with regards to stinging, though, we'd encourage you to live with the relatively brief period of bee activity if possible.
Miri
